GtkHeaderBar: Fix a corner-case in child properties

The child property setting must be prepared to deal with any
child property for any child, even if it doesn't make sense,
like the pack-type for the custom title. This is happening
in glade when undoing a change in the custom-title property.
Adwaita: add borders to menus in a non composited env

https://bugzilla.gnome.org/show_bug.cgi?id=738800
gtkmenu: fix unnecessary scroll buttons

Don't change menu height if menu is out of monitor only by shadow
width.

https://bugzilla.gnome.org/show_bug.cgi?id=738321
GtkFileChooser: Add a menuitem for 'sort directories first'

This has been requested repeatedly.
GtkIconTheme: Improve an error message

Mention the name of the theme when an icon lookup fails.
https://bugzilla.gnome.org/show_bug.cgi?id=687963
Only warn once if inhibit-related dbus calls fail

No need to spam about it.

https://bugzilla.gnome.org/show_bug.cgi?id=734140
GtkGLArea: Add create-context signal

This lets you hook into the GL context creation which is useful
if you want to share one GL context between GtkGLArea widgets.
GtkGLArea: Don't dispose gl context on unrealize

This was done to ensure the context is not current, but this is
pretty broken for shared contexts. We now just make it non-current.
GdkGLContext: Add display property

We need to use this in the code path where we make the context
non-current during destroy, because at that point the window
could be destroyed and gdk_window_get_display() would return
NULL.
GtkGLArea: Correctly position/size input window on realize
Add some more builder tests
Make window scale changes work again

Commit afd9709afff151e04b84b91c6d90b7 made us keep impl window
cairo surfaces around across changes of window scale. But the
window scale setter forgot to update the size and scale of the
surface. The effect of this was that toggling the window scale
from 1 to 2 in the inspector was not causing the window to draw
at twice the size, although the X window was made twice as big,
and input was scaled too. Fix this by updating the surface when
the window scale changes.
Adwaita: brighter dark variant header-bar bottom shade
Updated Hebrew translation
Updated Hebrew properties translation
gtkwindow: Do not create the multipress gesture for plugs

GtkPlugs may "qualify" as toplevels, even though they're not meant to
be WM manipulated, so refuse to create the multipress gesture for these
too.
gtkwindow: Resort to regular event bubbling by all means on non-toplevels

If the multipress gesture is not created (ie. not a toplevel GtkWindow),
also avoid possibly calling gtk_widget_event() on the events gotten here.
GtkHeaderBar: Make the position child property writable

Glade asssumes that it is, and without this, rearranging children
in glade is very cumbersome.
mir: Don't assert on unknown Mir events.

If we get a Mir event we don't understand generate a warning instead of an assert.
GdkGL: Fix and clean up gdk_cairo_draw_from_gl()

This was unnecessarily creating a framebuffer in the texture case,
and it was not properly setting up a framebuffer with the texture
as source in the software fallback w/ texture source case.